Understanding the effects of aging on the brain has been the focus of decades of research in clinical, cognitive, and basic neuroscience. This area has gained increasing popularity as the aging "baby-boomers" deal with their aging issues as well as those of their parents. Although much as been learned about normal brain changes with aging, the many factors that affect cognitive efficiency in the second half of life are only beginning to be understood. The "use it or lose it" philosophy seems to apply well to brain function, and data are accumulating to support this long-held but often ignored notion. Whereas neuroscience has shown that enriched environments enhance dendritic connections and complexity early in life, it is becoming clear that maximizing brain/body health and continuing an active mental life throughout adulthood also play roles in maximizing cognitive efficiency as we age. Keeping Your Brain Young serves a timely role in addressing many of these issues in a format that will have wide appeal.